For EU RoHS, since the Cr6+ is a sacrificial layer removed from the laminate
prior to use in a product there is no issue (assuming it's COMPLETELY removed).
However, for China's RoHS-like law, the use of Cr6+ in the fabrication
process does not seem to be allowed by Article 10 of the law (for products
that are intended for the Chinese domestic market). How they would enforce
that for PCBs manufactured outside China is unclear.
See http://www.chinarohs.com for translations of the law.
Michael Kirschner
President
Design Chain Associates, LLC
866-DCA-7676 x2
On Wed, 22 Mar 2006 13:34:10 -0500, Steve Kelly <[log in to unmask]> wrote:
>I agree with this but how do the material suppliers say the material is
>RoHS compliant? Is the chromate level below the RoHS directive? Regards
>Steve kelly
>
>Steve Kelly
>PH: (416) 750-8433
>FAX: (416) 750-0016
>CELL: (416) 577-8433
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Barmuta, Mike
>Sent: Wednesday, March 22, 2006 1:20 PM
>To: [log in to unmask]
>Subject: Re: [TN] chromates on copper surface (Cr6)?
>
>Hi Dave: Yes; Hexavalent chrome (Cr6) on aluminum such as electronic
>chassis is definitely non-compliant. And should not be confused with Cr6
>coatings on Cu laminate that are removed in processing.
>
>Bottom line is you don't want Cr6 in your finished product. That's why
>we are investigating some of the new NCP coatings but I still have my
>reservations on class 1A performance.
>
>
>Mike B.
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
>Sent: Wednesday, March 22, 2006 10:06 AM
>To: [log in to unmask]
>Subject: Re: [TN] chromates on copper surface (Cr6)?
>
>Hi Mike! Part of the confusion could be that the TechNet threads are
>discussing chromate conversion coatings on copper which can be shown to
>not
>be present in/on the final laminate as Cr+6. Another introduction of
>chromate conversion coating in an electronics assembly is as a corrosion
>protection coating on aluminum sheet metal surfaces. The Cr+6 species is
>present in the "delivered" product in that case causing RoHS compliance
>issues.
>
>Dave
>
>
>
> "Barmuta, Mike"
> <Mike.Barmuta@FLU
> KE.COM>
>To
> Sent by: TechNet [log in to unmask]
> <[log in to unmask]>
>cc
>
>
>Subject
> 03/22/2006 11:48 Re: [TN] chromates on copper
> AM surface (Cr6)?
>
>
> Please respond to
> TechNet E-Mail
> Forum
> <[log in to unmask]>
> ; Please respond
> to
> "Barmuta, Mike"
> <Mike.Barmuta@FLU
> KE.COM>
>
>
>
>
>
>
>Hi All: Maybe I'm missing something in this whole Cr6 laminate thread
>but I see it as a non-issue.
>
>Most of these chromate coatings are extremely thin 200-300 angstroms
>i.e. a millionth of an inch.
>Hot alkaline chemistry, strong acidic chemistries or mechanical surface
>prep strip the chromate conversion coating from the surface of the
>copper foil. So whether you are processing innnerlayers in a cleaning or
>oxide process or outerlayers in a cleaning or metallization process the
>presence of alkaline cleaners, surface treatments and/or acidic micro
>etches will remove the thin deposit of chromate coating from the foil.
>Thus making it RoHS compliant.
>
>
>
>Regards
>
>Michael Barmuta
>
>Staff Engineer
>
>Fluke Corp.
>
>Everett WA
>
>425-446-6076
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeffrey Bush
>Sent: Wednesday, March 22, 2006 9:06 AM
>To: [log in to unmask]
>Subject: Re: [TN] chromates on copper surface (Cr6)?
>
>High presence of Cr3/Cr6 will cause issues with oxide treatment when
>using reduction/replacement chemistries. The chem clean process prior
>to resist lamination is designed to reduce the Cr3 to levels not
>affecting etch, strip and bonding treatment. Detecting levels related
>to this would seem to be evident in other areas in the process.
>
>Jeffrey Bush
>Director, Quality Assurance and Technical Support
>VERMONT CIRCUITS INCORPORATED
> 76 Technology Drive - POB 1890
> Brattleboro, Vermont 05302
> Voice - 802.257.4571 ext 21
> Fax - 802.257.0011
> <http://www.vtcircuits.com/>
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Eddie Rocha
>Sent: Wednesday, March 22, 2006 10:45 AM
>To: [log in to unmask]
>Subject: Re: [TN] chromates on copper surface (Cr6)?
>
>A few responses are saying this same thing, that it won't
>be present after fabrication. I'll have to test it for
>myself because I have a customer that detected Cr. But the
>customer doesn't know which state of Cr. Do we just assume
>it is Cr3 and not Cr6?
>
>Thank you,
>Eddie Rocha
>
>
>
>If the Cu on the laminate is Cr+6 passivated on receipt, it
>won't be by
>the time you've prepared it for lamination as surely the
>pretreatment
>will remove the passivation layer?
>
>Regards
>Ian Fox
>Goodrich ECS
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of David
>D. Hillman
>Sent: 22 March 2006 00:03
>To: [log in to unmask]
>Subject: Re: [TN] chromates on copper surface (Cr6)?
>
>Hi Eddie! Just to add to Rudy's comments - any chromate
>conversion
>coating that is Cr+6 based does convert to Cr+3 when
>damaged (e.g. the
>self healing
>aspect) but there is always some of the Cr+6 species
>around. Any
>chromate conversion coating that is Cr+6 based is not RoHS
>compliant.
>Your supplier is incorrect unless he/she is supplying a
>Cr+3 or zero
>chromate conversion coating as Rudy described. Qualifying a
>substitute
>conversion coating that is "as good as or better than" a
>Cr+6 conversion
>coating is not an easy task depending on your use
>environment
>conditions. Good Luck.
>
>Dave
>
>
>
> Eddie Rocha
> <[log in to unmask]
> M>
>To
> Sent by: TechNet [log in to unmask]
> <[log in to unmask]>
>cc
>
>
>Subject
> 03/21/2006 05:56 Re: [TN] chromates
>on copper
> PM surface (Cr6)?
>
>
> Please respond to
> TechNet E-Mail
> Forum
> <[log in to unmask]>
> ; Please respond
> to
> Eddie Rocha
> <[log in to unmask]
> M>
>
>
>
>
>
>
>Was this a tough question? I didn't receive but one
>response. Thanks
>Rudy.
>
>
>
>
>Eddie:
>
>Not clear I can "explain" something which is likely
>incorrect.
>If your vendors start with Cr +6, the likelihood of there
>being zero
>Cr+6 on the foil is near zero... certainly some of the Cr
>+6 reacts with
>Copper metal Cu0 to form Cr+3 and
>Cu+2, but all of it? Hah... dream on.
>
>However, before you go off and begin screaming, I suspect
>strongly that
>some producers of foil may well be switching from Cr+6 to
>zero Cr
>coating... I cannot fathom why organics could not do as
>good a job...
>
>And if there are foil producers who need some technology to
>assist this
>change, contact me... :-)
>
>Rudy Sedlak
>RD Chemical Company
>
>Eddie Rocha <[log in to unmask]> wrote: I understand that
>copper foils
>are protected with chromates
>(Cr6) prior to producing laminate. Since this is an RoHS
>banned
>substance I need to understand why all my laminate
>suppliers have
>certified their material to be RoHS compliant.
>
>One supplier responded by stating that Cr6 is reduced to a
>state of Cr3
>or Cr0 which is not a restricted substance.
>
>Can somebody explain how it goes from a state of Cr6 to one
>of the
>reduced states and why sometimes Cr3 versus Cr0?
>
>
>Thank you,
>Eddie Rocha
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
